To determine the significance of the endoscopic classification of gastritis proposed by a working party at the World Congress of Gastroenterology in Sydney 1990, 167 patients undergoing upper alimentary endoscopy were prospectively assessed by comprehensive endoscopic and histological methods. Ninety eight patients had endoscopic mucosal changes of gastritis according to the Sydney classification. Twenty six (27%) of these had histologically normal biopsy specimens. This was not statistically significantly different to the 26 (38%) of 69 with normal endoscopies whose biopsy specimens were histologically normal (chi 2 = 1.857, p > 0.1). Forty three (62.5%) patients with normal endoscopies had histological gastritis. No histological counterpart was found for the macroscopic appearances of the gastric mucosa said to show inflammation proposed by the Sydney classification of gastritis. These findings confirm the inappropriateness of an endoscopic diagnosis of gastritis and it is suggested such a term should be reserved for the histological findings.